As rare as hen's teeth? Not any more, say scientists

If you thought hen's teeth were the rarest thing in nature, think again: researchers from Britain and the US have succeeded in growing teeth in a chicken.

Far from being rarer than students who turn up at 9am lectures or lecturers who like giving them, a hen with teeth does occur naturally, scientists based at the universities of Manchester and Wisconsin have found.

And by studying that mutant chicken - which is too weak to hatch, explaining its rarity - the team has been able to stimulate "natural" tooth growth in chickens.

The mutant chicken harks back to toothier days: the ancestors of today's birds lost their teeth about 80 million years ago, but not the ability to grow them.

Dr Matthew Harris, the lead researcher from Wisconsin, told how scientists were able to isolate the usually latent genetic "pathway" that leads to tooth growth - and create the "initiations of early teeth".

"We turned on a gene that is involved with the earliest steps of making organs from the skin, like hairs and glands and teeth.

"We turned on this gene in the oral cavity and saw that the underlying tissue was able to respond to the signal."

The work is a breakthrough, says Dr Harris, because for the first time, the teeth created in the chicken are natural rather than imported from another animal.

"We've put bits of mice into chicken and got a mouse tooth," he says. "The big deal is that we didn't do anything to this chicken. It was a naturally occurring mutant."

Professor Mark Ferguson, a member of the team at the University of Manchester, says the research on reactivation of dormant genetic pathways could ultimately help treat sufferers of scarring, where tissue regeneration is needed.

As for whether the research could be used to regrow human teeth, Professor Ferguson says that is "wild speculation" - in other words, about as likely as hen's teeth.